Alert archive / Ohio / Mesoscale Discussions in 2021

Mesoscale Discussion 1600

August 25, 202133 counties in Indiana; 9 counties in Kentucky; 39 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Aug 25, 2021, 12:46 PM EDT for 33 counties in Indiana; 9 counties in Kentucky; 39 counties in Ohio. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 25, 2021, 12:46 PM EDT (16:46 UTC)
Expired: Aug 25, 2021, 3:15 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

All 81 counties

Bartholomew County, IN, Boone County, IN, Brown County, IN, Clay County, IN, Dearborn County, IN, Decatur County, IN, Fayette County, IN, Franklin County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Johnson County, IN, Madison County, IN, Marion County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Ohio County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Ripley County, IN, Rush County, IN, Scott County, IN, Shelby County, IN, Switzerland County, IN, Tipton County, IN, Union County, IN, Wayne County, IN, Boone County, KY, Bracken County, KY, Campbell County, KY, Carroll County, KY, Gallatin County, KY, Grant County, KY, Kenton County, KY, Pendleton County, KY, Trimble County, KY, Adams County, OH, Athens County, OH, Brown County, OH, Butler County, OH, Champaign County, OH, Clark County, OH, Clermont County, OH, Clinton County, OH, Coshocton County, OH, Delaware County, OH, Fairfield County, OH, Fayette County, OH, Franklin County, OH, Greene County, OH, Guernsey County, OH, Hamilton County, OH, Harrison County, OH, Highland County, OH, Hocking County, OH, Holmes County, OH, Jackson County, OH, Knox County, OH, Licking County, OH, Madison County, OH, Montgomery County, OH, Morgan County, OH, Morrow County, OH, Muskingum County, OH, Noble County, OH, Perry County, OH, Pickaway County, OH, Pike County, OH, Preble County, OH, Ross County, OH, Tuscarawas County, OH, Union County, OH, Vinton County, OH, Warren County, OH, Washington County, OH

The radar

The Cincinnati radar (KILN), 47 km from the middle of the area, began a volume at 16:48 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 12:00Z, 4.8 hours before the alert went out and 46 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1234 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 1127 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 97 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

492 
ACUS11 KWNS 251647
SWOMCD
SPC MCD 251646 
OHZ000-KYZ000-INZ000-251915-

Mesoscale Discussion 1600
NWS Storm Prediction Center Norman OK
1146 AM CDT Wed Aug 25 2021

Areas affected...Much of Ohio...indiana and northern kentucky

Concerning...Severe potential...Watch unlikely 

Valid 251646Z - 251915Z

Probability of Watch Issuance...5 percent

SUMMARY...Scattered thunderstorm development underway early this
afternoon may pose some risk for damaging down burst winds.
Widespread severe storms are not expected.

DISCUSSION...As of 1640 UTC, regional radar and satellite imagery
showed scattered thunderstorms developing in proximity to a weak MCV
from previous convection. Aloft, a weakness within the ridge
upstream is supporting subtle ascent across much of the upper Ohio
valley.  Along with the weak forcing for ascent, diurnal heating of
a seasonably moist airmass with dewpoints in the 60s and 70s F is
supporting 1500-2000 J/kg of MLCAPE. Vertical shear is quite weak
with the 12z KILN sounding indicating less than 15 kt of effective
shear. This is reflected by the primarily pulse multicell mode of
ongoing storms. As additional convection develops this afternoon a
few strong wind gusts may occur given steep low-level lapse rates
favorable for downbursts. However, little potential for storm
organization and a resulting greater sever risk exists, negating the
need for a weather watch.

..Lyons/Kerr.. 08/25/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PBZ...RLX...CLE...ILN...LMK...IND...

LAT...LON   40348591 39978519 39818483 39898443 40118411 40318385
            40428338 40668275 40798199 40758143 40538102 40068099
            39528137 39118207 38868300 38638388 38538475 38628569
            38988679 39588747 40138719 40348591

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 24, 9:14 PM EDT	Mesoscale Discussion	SPC	Elkhart, LaGrange, Lake, LaPorte, Marshall, Newton and 4 more	2 hr
Aug 25, 5:02 PM EDT	Mesoscale Discussion	SPC	Vermillion, Warren	88 min

Nearby

Mesoscale Discussions in Ohio, 2021 Mesoscale Discussions in Indiana, 2021 Mesoscale Discussions in Kentucky, 2021 Every mesoscale discussion in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.